plz answer dis

Asked by  | 5th Feb, 2010, 06:16: PM

Expert Answer:

 

DNA copying is an essential event in reproduction. Here cells build copies of their DNA, thereby producing two DNA copies in a reproducing cell, which then needs to be separated from each other. Hence, DNA copying is accompanied by the creation of an additional cellular apparatus, and then the DNA copies separate, each with its own cellular apparatus. Thus a cell divides to give rise to two cells.                                                                                                                                               

                                                                                                                                                       

 

There may be variations in the the DNA copying reactions occuring during reproduction, since no biochemical reactions are absolutely reliable. As a result, the DNA copies generated will be similar, but may not be identical to the original. Some of these variations might be so drastic that the new DNA copy cannot work with the cellular apparatus it inherits. Such a newborn cell will simply die. On the other hand, there could still be many other variations in the DNA copies that would not lead to such a drastic outcome. Thus, the surviving cells are similar to, but subtly different from each other. This inbuilt tendency for variation during reproduction is the basis for evolution. The consistency of DNA copying during reproduction is important for the maintenance of body design features that allow the organism to use that particular niche. Reproduction is therefore linked to the stability of populations of species.

 

Answered by  | 5th Feb, 2010, 07:43: PM

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